In recent years, considerable progress has been made towards the development of thin and flexible displays. U.S. Pat. No. 6,639,578 cites a process for creating an electronically addressable display that includes multiple printing operations, similar to a multi-color process in conventional screen printing. Likewise, U.S. Pat. Application No. 2006/0007368 cite a display device assembly comprising a flexible display device being rollable around an axis. A range of flexible electronic devices based on these technologies, including full color, high-resolution flexible OLED displays with a thickness of 0.2 mm are being introduced to the market (14). The goal of such efforts is to develop displays that resemble the superior handling, contrast and flexibility of real paper.
As part of this invention we devised an apparatus for tracking interaction techniques for flexible displays that uses a projection apparatus that projects images generated by a computer onto real paper, of which the shape is subsequently measured using a computer vision device. Deformation of the shape of the paper display is then used to manipulate in real time said images and/or associated computer functions displayed on said display. It should be noted that the category of displays to which this invention pertains is very different from the type of rigid-surface LCD displays cited in, for example, U.S. Pat. Nos. 6,567,068 or 6,573,883 which can be rotated around their respective axes but not deformed.
Prior art, which include bendable interfaces such as ShapeTape (1) and Gummi (20) demonstrates the value of incorporating the deformation of computing objects for use as input for computer processes. However, in this patent, we propose methods for interacting with flexible displays that rely on deformations of the surface structure of the display itself. While this extends work performed by Schwesig et al (17), which proposed a credit card sized computer that uses physical deformation of the device for browsing of visual information, it should be noted that said device did not incorporate a flexible material, and did not use deformation of the display. Instead, it relied on the use of touch sensors mounted on a rigid LCD-style display body.
The use of projection to simulate computer devices on three dimensional objects is also cited in prior art. SmartSkin (18) is an interactive surface that is sensitive to human finger gestures. With SmartSkin, the user can manipulate the contents of a digital back-projection desk using manual interaction. Similarly, Rekimoto's Pick and Drop (16) is a system that lets users drag and drop digital data among different computers by projection onto a physical object. In Ishii's Tangible User Interface (TUI) paradigm (5), interaction with projected digital information is provided through physical manipulation of real-world objects. In all of such systems, the input device is not the actual display itself, or the display is not on the actual input device. With DataTiles (17), Rekimoto et. al. proposed the use of plastic surfaces as widgets that with touch-sensitive control properties for manipulating data projected onto other plastic surfaces. Here, the display surfaces are again two-dimensional and rigid body.
In DigitalDesk (24), a physical desk is augmented with electronic input and display. A computer controlled camera and projector are positioned above the desk. Image processing is used to determine which page a user is pointing at. Object character recognition transfers content between real paper and electronic documents projected on the desk. Wellner demonstrates the use of his system with a calculator that blurs the boundaries between the digital and physical world by taking a printed number and transferring it into an electronic calculator. Interactive Paper (11) provides a framework for three prototypes. Ariel (11) merges the use of engineering drawings with electronic information by projecting digital drawings on real paper laid out on a planar surface. In Video Mosaic (11), a paper storyboard is used to edit video segments. Users annotate and organize video clips by spreading augmented paper over a large tabletop. Caméléon (11) simulates the use of paper flight strips by air traffic controllers, merging them with the digital world. Users interact with a tablet and touch sensitive screen to annotate and obtain data from the flight strips. Paper Augmented Digital Documents (3) are digital documents that are modified on a computer screen or on paper. Digital copies of a document are maintained in a central database and if needed, printed to paper using IR transparent ink. This is used to track annotations to documents using a special pen.
Insight Lab (9) is an immersive environment that seamlessly supports collaboration and creation of design requirement documents. Paper documents and whiteboards allow group members to sketch, annotate, and share work. The system uses bar code scanners to maintain the link between paper, whiteboard printouts, and digital information.
Xlibris (19) uses a tablet display and paper-like interface to include the affordances of paper while reading. Users can read a scanned image of a page and annotate it with digital ink. Annotations are captured and used to organize information. Scrolling has been removed from the system: pages are turned using a pressure sensor on the tablet. Users can also examine a thumbnail overview to select pages. Pages can be navigated by locating similar annotations across multiple documents. Fishkin et al. (2) describe embodied user interfaces that allow users to use physical gestures like page turning, card flipping, and pen annotation for interacting with documents. The system uses physical sensors to recognize these gestures. Due to space limitations we limit our review: other systems exist that link the digital and physical world through paper. Examples include Freestyle (10), Designers' Outpost (8), Collaborage (12), and Xax (6). One feature common to prior work in this area is the restriction of the use of physical paper to a flat surface. Many project onto or sense interaction in a coordinate system based on a rigid 2D surface only. In our system, by contrast, we use as many of the three dimensional affordances of flexible displays as possible.
In Illuminating Digital Clay (15), Piper et al. proposed the use of a laser scanner to determine the deformation of a clay mass. This deformation was in turn used to alter images projected upon the clay mass through a projection apparatus. The techniques presented in this patent are different in a number of ways. Firstly, our display unit is completely flexible, can be duplicated to work in unison with other displays of the same type and move freely in three-dimensional space. They can be folded 180 degrees around any axis or sub-axes, and as such completely implement the functionality of two-sided flexible displays. Secondly, rather than determining the overall shape of the object as a point cloud, our input techniques rely on determining the 3D location of specific marker points on the display. We subsequently determine the shape of the display by approximating a Bezier curve with control points that coincide with these marker locations, providing superior resolution. Thirdly, unlike Piper (15), we propose specific interaction techniques based on the 3D manipulation and folding of the display unit. The advantages of regular paper over the windowed display units used in standard desktop computing are manifold (21). In the Myth of the Paperless Office (21) Sellen analyzes the use of physical paper. She proposed a set of design principles for incorporating affordances of paper documents in the design of digital devices, such as 1) Support for Flexible Navigation, 2) Cross Document Use, 3) Annotation While Reading and 4) Interweaving of Reading and Writing.
Documents presented on paper can be moved in and out of work contexts with much greater ease than with current displays. Unlike GUI windows or rigid LCD displays, paper can be folded, rotated and stacked along many degrees of freedom (7). It can be annotated, navigated and shared using extremely simple gestural interaction techniques. Paper allows for greater flexibility in the way information is represented and stored, with a richer set of input techniques than currently possible with desktop displays. Conversely, display systems currently support properties unavailable in physical paper, such as easy distribution, archiving, querying and updating of documents. By merging the digital world of computing with the physical world of flexible displays we increase value of both technologies.